Substituted cephalosporins as anti-inflammatory and antidegenerative agents

ABSTRACT

Substituted cephalosporins are found to be potent elastase inhibitors and thereby useful antiinflammatory/antidegenerative agents.

BACKGROUND OF THE INVENTION

We have found that substituted cephalosporins are potent elastase inhibitors and therefore are useful anti-inflammatory/antidegenerative agents.

Proteases from granulocytes and macrophages have been reported to be responsible for the chronic tissue destruction mechanisms associated with inflammation, including rheumatoid arthritis and emphysema. Accordingly, specific and selective inhibitors of these proteases are candidates for potent anti-inflammatory agents useful in the treatment of inflammatory conditions resulting in connective tissue destruction, e.g. rheumatoid arthritis, emphysema, bronchial inflammation, osteoarthritis, spondylitis, lupus, psoriasis and acute respiratory distress syndrome.

The role of proteases from granulocytes, leukocytes or macrophages are related to a rapid series of events which occurs during the progression of an inflammatory condition:

(1) There is a rapid production of prostaglandins (PG) and related compounds synthesized from arachidonic acid. This PG synthesis has been shown to be inhibited by aspirin-related nonsteroidal anti-inflammatory agents including indomethacin and phenylbutazone. There is some evidence that protease inhibitors prevent PG production;

(2) There is also a change in vascular permeability which causes a leakage of fluid into the inflamed site and the resulting edema is generally used as a marker for measuring the degree of inflammation. This process has been found to be induced by the proteolytic or peptide cleaving activity of proteases, especially those contained in the granulocyte, and thereby can be inhibited by various synthetic protease inhibitors, for example, N-acyl benzisothiazolones and the respective 1,1-dioxides. Morris Zimmerman et al., J. Biol. Chem., 255, 9848 (1980); and

(3) There is an appearance and/or presence of lymphoid cells, especially macrophages and polymorphonuclear leukocytes (PMN). It has been known that a variety of proteases are released from the macrophages and PMN, further indicating that the proteases do play an important role in inflammation.

In general, proteases are an important family of enzymes within the peptide bond cleaving enzymes whose members are essential to a variety of normal biological activities, such as digestion, formation and dissolution of blood clots, the formation of active forms of hormones, the immune reaction to foreign cells and organisms, etc., and in pathological conditions such as the degradation of structural proteins at the articular cartilage/pannus junction in rheumatoid arthritis etc.

Elastase is one of the proteases. It is an enzyme capable of hydrolyzing the connective tissue component elastin, a property not contained by the bulk of the proteases present in mammals. It acts on a protein's nonterminal bonds which are adjacent to an aliphatic amino acid. Neutrophil elastase is of particular interest because it has the broadest spectrum of activity against natural connective tissue substrates. In particular, the elastase of the granulocyte is important because, as described above, granulocytes participate in acute inflammation and in acute exacerbation of chronic forms of inflammation which characterize many clinically important inflammatory diseases.

Proteases may be inactivated by inhibitors which block the active site of the enzyme by binding tightly thereto. Naturally occurring protease inhibitors form part of the control or defense mechanisms that are crucial to the well-being of an organism. Without these control mechanisms, the proteases would destroy any protein within reach. The naturally occurring enzyme inhibitors have been shown to have appropriate configurations which allow them to bind tightly to the enzyme. This configuration is part of the reason that inhibitors bind to the enzyme so tightly (see Stroud, "A Family of Protein-Cutting Proteins" Sci. Am. July 1974, pp. 74-88). For example, one of the natural inhibitors, α₁ -Antitrypsin, is a glycoprotein contained in human serum that has a wide inhibitory spectrum covering, among other enzymes, elastase both from the pancreas and the PMN. This inhibitor is hydrolyzed by the proteases to form a stable acyl enzyme in which the active site is no longer available. Marked reduction in serum α₁ -antitrypsin, either genetic or due to oxidants, has been associated with pulmonary emphysema which is a disease characterized by a progressive loss of lung elasticity and resulting respiratory difficulty. It has been reported that this loss of lung elasticity is caused by the progressive, uncontrolled proteolysis or destruction of the structure of lung tissue by proteases such as elastase released from leukocytes. J. C. Powers, TIBS, 211 (1976).

Rheumatoid arthritis is characterized by a progressive destruction of articular cartilage both on the free surface bordering the joint space and at the erosion front built up by synovial tissue toward the cartilage. This destruction process, in turn, is attributed to the protein-cutting enzyme elastase which is a neutral protease present in human granulocytes. This conclusion has been supported by the following observations:

(1) Recent histochemical investigations showed the accumulation of granulocytes at the cartilage/pannus junction in rheumatoid arthritis; and

(2) a recent investigation of mechanical behavior of cartilage in response to attack by purified elastase demonstrated the direct participation of granulocyte enzymes, especially elastase, in rheumatoid cartilage destruction. H. Menninger et al., in Bioloqical Functions of Proteinases, H. Holzer and H. Tschesche, eds. Springer-Verlag, Berlin, Heidelberg, New York, 1979, pp. 196-206.

Accordingly, an object of this invention is to discover new protease inhibitors, especially elastase inhibitors, useful for controlling tissue damage and various inflammatory or degenerative conditions mediated by proteases particularly elastase.

Another object of the present invention is to provide pharmaceutical compositions for administering the active substituted cephalosporin sulfoxides as protease inhibitors.

Still a further object of this invention is to provide a method of controlling inflammatory conditions by administering a sufficient amount of one or more of the active, substituted cephalosporin sulfoxides in a mammalian species in need of such treatment.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to cephalosporins as potent elastase inhibitors useful in the prevention, control and treatment of inflammatory conditions especially arthritis and emphysema.

Some of the cephalosporin free acids are known antibiotics which have been described in U.S. Pat. No. 4,297,488 issued Oct. 27, 1981.

The structural formula of the cephalosporin esters of the present invention are represented as follows: ##STR1## wherein M is: (1) trifluoromethyl:

(2) chloro or fluoro:

(3) --COOH:

(4) --CHO: or

(5) --CH₂ A wherein A represents

(a) hydrogen;

(b) halo;

(c) hydroxy;

(d) alkoxy;

(e) aryloxy;

(f) aralkyloxy;

(g) unsubstituted or substituted mercapto;

(h) acylthio;

(i) acyloxy especially alkanoyloxy or arylcarbonyloxy such as acetoxy, α-aminophenylacetoxy, benzyloxycarbonyloxy, benzoyloxy; and succinoyloxy; substituted or unsubstituted carbamoyl, thiocarbamoyl and N-alkyl or N,N-dialkyl derivatives thereof;

(j) a quaternary ammonium group, for example, --N.sup.⊕ H₃, --N.sup.⊕ HE², or --N.sup.⊕ E³ where E represents loweralkyl, aryl or aralkyl;

(k) unsubstituted or substituted amino or amido group especially --NH₂, --CONH₂ and N-alkyl or N,N-dialkyl derivatives thereof.

Thus, CH₂ A can be a halomethyl such as chloromethyl, bromomethyl or fluoromethyl.

When CH₂ A is a substituted hydroxy or substituted mercapto group, it can be shown by the formula

--CH₂ ZR₅

where Z is oxygen or sulfur, and R₅ is an acyl group; a straight chain or branched chain loweralkyl, alkenyl or alkynyl group; an aryl group; an aralkyl group; or a heterocyclic group such as heteroaryl, heterocycloalkyl e.g., 1,3-dioxacyclohex-4-yl, piperidino, morpholino, oxacyclopropyl, pyrrolidino, tetrazolo, benzothiazolo, imidazolidino, pyrazolidino, and piperazino; or heterocycloalkenyl such as pyrrolino, 2-imidazolino, 3-pyrazolino or isoindolino. These groups can be unsubstituted or can be substituted by radicals such as alkyl, alkoxy, halo, cyano, carboxy, carbamoyl, azido, sulfo, amino, substituted amino, haloalkyl, carboxyalkyl, carbamoylalkyl, N-substituted carbamoylalkyl, guanidino, N-substituted guanidino, guanidoalkyl, sulfamyl, substituted sulfamyl, and the like. Representative of the --CH₂ A groups are methoxymethyl, n-propoxymethyl, methylthiomethyl, acetoxymethyl, propionyloxymethyl, benzoyloxymethyl, (p-chlorobenzoyl)oxymethyl, succinoyloxymethyl, (p-methylbenzoyl)oxymethyl, pivaloyloxymethyl, (1-adamantyl)-carboxymethyl, butanoyloxymethyl, carbamoyloxymethyl, (N-methylcarbamoyl)oxymethyl, (N-ethylcarbamoyl)oxymethyl, [N-(2-chloroethyl) carbamoyl]oxymethyl, (N-phenylcarbamoyl)oxymethyl, [N-(carboxymethyl)-carbamoyl]oxymethyl, (N-p-sulfophenyl-carbamoyl)oxymethyl, p-carboxymethylphenyl-carbamoyloxymethyl, methoxycarbonyloxymethyl, isobutanoyloxymethyl, cyclobutylcarbonyloxymethyl, carbamoylthiomethyl, (ethoxythiocarbonyl)thiomethyl, (n-propoxythiocarbonyl) thiomethyl, (cyclopentanoxythiocarbonyl)thiomethyl, methylthiomethyl, N,N-diethylthiocarbamoylthiomethyl, N-methylpiperazinium-1-thiocarbonylthiomethyl, N,N-dimethylpiperazinium-1-thiocarbonylthiomethyl, 2-furoylthiomethyl, isothiouroniummethyl, (5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl, p-tolylsulfonylthiomethyl, 2-benzothiazolothio-methyl, mesyloxymethyl, 1-methyl-1,2,3,4-tetrazolyl-5-thiomethyl, tosyloxymethyl, sulfamoyloxymethyl, 1-naphthoyloxymethyl, 2-furylacetoxymethyl, cinnamoyloxymethyl, p-hydroxycinnamoyloxymethyl, p-sulfocinnamoyloxymethyl and 1R:2S-epoxypropylphosphonyloxymethyl.

Alternatively, when CH₂ A is hydroxymethyl, the cephalosporin can also exist as the lactone which is formed by internal esterification with the adjacent carboxy group.

The substituent CH₂ A can also be a group of the general formula

    --CH.sub.2 Y.sub.1

wherein Y₁ represents amino or substituted amino including nitrogen heterocycles and substituted heterocyclic groups as described for R₅. Y₁ may also be nitrogen which is part of the heterocyclic system as shown below. ##STR2## Examples of such groups that might be mentioned are aminomethyl, acetamidomethyl, carbamoylaminomethyl, N,N-dimethylaminomethyl, N-(2-chloroethyl)aminomethyl, 5-cyano-triazol-1-yl-methyl, 4-methoxycarbonyltriazol-1-yl-methyl.

When A is amino the cephalosporin compound can also exist as the lactam formed by loss of water with the adjacent carboxy group.

Representative of the quaternary ammonium groups representing A that might be mentioned are pyridinium, 3-methylpyridinium, 4-methylpyridinium, 3-chloropyridinium, 3-bromopyridinium, 3-iodopyrinium, 4-carbamoylpyridinium, 4-(N-hydroxymethylcarbamoyl)pyridinium, 4-(N-carbomethoxycarbamoyl)pyridinium, 4-(N-cyanocarbamoyl)pyridinium, 4-carboxymethylpyridinium, 4-hydroxymethylpyridinium, 4-trifluoromethyl-pyridinium, quinolinium, picolinium and lutidinium.

When A is mercapto, it may be -SH, ##STR3## alkylthio, arylthio, aralkylthio or heterocyclothio, wherein R represents C₁₋₆ alkyl.

The preferred groups representing A are (a) hydrogen; (b) halo; (c) hydroxy; (d) alkoxy; (e) aryloxy; (f) aralkyloxy; (g) substituted or unsubstituted mercapto especially ##STR4## (h) acylthio; or (i) acyloxy. The acyl group can be a loweralkanoyl group of 2-6 carbon atoms such as acetyl, --COC₂ H₅ or --COC₃ H₇, carbamoyl, or thiocarbamoyl and N-alkyl or N,N-dialkyl derivatives thereof. The alkyl group of the foregoing substituents contains 1-10 carbon atoms and may be further substituted by radicals such as alkoxy, halo, amino, cyano, carboxy, sulfo, and the like.

More preferably, A is

(a) alkanoyloxy especially ##STR5## (b) C₁₋₃ alkoxy especially methoxy, ethoxy or i- or n-propyloxy;

(c) halo;

(d) hydrogen;

(e) hydroxy;

(f) substituted or unsubstituted mercapto; or

(g) carbamoyloxy, especially L- or D- form of ##STR6##

The substituent R₁ in formula (I) above can be

(a) hydrogen;

(b) hydroxy;

(c) mercapto;

(d) substituted oxy;

(e) substituted thio;

(f) hydrocarbyl or substituted hydrocarbyl group;

(g) cyano;

(h) carbonyl or thiocarbonyl containing substituents bonded by said carbonyl or thiocarbonyl radical;

(i) halo;

(j) phosphono or a substituted phosphono group.

The oxy or thio substituent represented by R₁ in formula (I) can be a substituted hydroxy or mercapto group such as --XR'₁ herein X is oxygen or sulfur and R'₁ is a hydrocarbyl group, preferably a straight or branched loweralkyl group of 1-6 carbon atoms, a straight or branched chain loweralkenyl or loweralkynyl group of 3-6 carbon atoms, a monocyclic aryl group such as phenyl, furyl, pyrryl and pyridyl, or an aralkyl group such as benzyl. These alkyl, alkenyl, alkynyl, aryl or aralkyl groups can be substituted with groups such as hydroxy, halo, nitro, amino, carboxy, thio, and the like. Other specific substituents represented by R₁ that might be mentioned are groups of the formula --OAc, --SAc, --SO₃ H, --SO₂ NH₂, --OCD₃, --SO₂ R₂, --SO₂ NR₃ R₄, --OCOOR₂, --SOR₂, --OCOSR₂, --OCONR₃ R₄, and the like wherein Ac represents an acyl group such as a formyl or loweralkanoyl, R₃ and R₄ represent hydrogen, loweralkyl, acyl and loweralkoxy, and R₂ represents loweralkyl, haloloweralkyl, aryl, aralkyl and substituted derivatives of such groups.

When R₁ is hydrocarbyl it can be straight or branched loweralkyl, straight or branched lower-alkenyl, loweralkynyl, aralkyl, cycloalkyl, a monocyclic aryl group, or a monocyclic heterocyclic group which can also be substituted with one or more groups such as halo, hydroxy, alkoxy, amino, nitro, sulfonyl, sulfamoyl, acyloxy, carbamoyloxy, carboxy, carboxamido and N-substituted carboxamido. Representative examples of such groups are C₁₋₆ alkyl such as methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, t-butyl; C₂₋₆ alkenyl especially allyl, α-butenyl; C₂₋₆ alkynyl such as ethynyl and methylethynyl; loweraralkyl such as benzyl, p-methoxybenzyl, phenethyl; phenyl, p-aminophenyl; cyclopropyl, cyclopentyl and 4-hydroxycyclohexyl;

R₁ in formula (I) above may also represent cyano or a group of the general formula ##STR7## wherein X' is oxygen or sulfur, and R" is hydrogen, halo, hydroxy, mercapto, amino, substituted amino, alkyl, aryl, aralkyl, aralkoxy such as benzyloxy, alkoxy or aryloxy such as phenoxy, pyrroloxy, furyloxy, and thienyloxy, alkylthio or arylthio. Examples of these substituents are --COOH, --CSSH, --COR₂, --COOR₂, --COSR₂, --CSSR₂, --CONH₂, --CSNH₂, --CSR₂, --CONHR₂, --CSNHR₂, --CONR₃ R₄ and --CSNR₃ R₄ wherein R₂ represents a straight or branched chain alkyl group of 114 6 carbon atoms and R₃ and R₄ represent hydrogen or R₂ ;

Furthermore, R₁ in formula (I) above represents disubstituted amino groups, nitro, azido, nitroso, isocyanato, isothiocyanato and hydroxyamino. Specific examples of nitrogen bonded groups that might be mentioned are --N₃, --NH₂, --NHR₂, NR₂ R₃, wherein R₂ represents a straight or branched chain loweralkyl group of 1 to 6 carbon atoms, R₃ represents R₂ or hydrogen, and n represents the integer 1 or 2.

Finally, the substituent R₁ in formula (I) represents phosphono or a metal or ammonium salt thereof, or a substituted phosphono group of the formula: ##STR8## where Y' and Z' are the same or different and represent ##STR9## where R₂ represents hydrogen or a hydrocarbyl radical, R₃ and R₄ represent hydrogen, hydrocarbyl, alkoxy or an acyl radical, and X' represents oxygen or sulfur.

Preferably, R₁ is

(1) hydroxy;

(2) OR₁, where R₁, represents hydrocarbyl group;

(3) C₁₋₆ alkylthio;

(4) C₁₋₆ alkylsulfinyl;

(5) C₁₋₆ alkylsulfonyl;

(6) halo such as fluoro, chloro, bromo or iodo; or;

(7) hydrogen; or

(9) C₁₋₆ alkyl.

Even more preferably, R₁ is

(1) C₁₋₃ alkyl;

(2) hydroxy;

(3) OR₁ 'where R₁ ' is p2 (a) C₁₋₆ alkyl especially methyl, ethyl, n-propyl;

(b) -C₆ H₅ ;

(c) -CH₂ CH₂ C₆ H₅ ; or

(d) ##STR10## where R represents hydrogen, C₁₋₆ alkyl, phenyl, substituted or unsubstituted benzyl, or C₁₋₆ alkylamino such as CH₃ NH--, C₂ H₅ NH--;

(4) halo especially Cl or F; or

(5) --SO₂ R.

B of Formula (I) above represents OB_(l), or NB₂ B₃ wherein B₁ and B₂ independently are:

(a) straight or branched chain alkyl having from 1 to 20 carbon atoms, ethyl, isopropyl, t-butyl, pentyl or hexyl;

(b) aryl having from 6 to 10 carbon atoms;

(c) cycloalkyl having from 3 to 8 carbon atoms;

(d) alkenyl having from 2 to 20 carbon atoms;

(e) cycloalkenyl having from 5 to 8 carbon atoms;

(f) alkynyl having from 2 to 20 carbon atoms;

(g) alkoxy having from 1 to 10 carbon atoms;

(h) aralkyl, alkaryl, aralkenyl, aralkynyl, alkenylaryl or alkynylaryl wherein alkyl, aryl, alkenyl and alkynyl are as previously defined;

(i) loweralkenylalkyl;

(j) alkanoylalkyl;

(k) alkanoyloxyalkyl;

(l) alkoxyalkyl;

(m) alkanoyloxy;

(n) a heterocyclic group including heterocyclic alkyl or heterocyclic alkenyl.

The above groups (a)-(n) can be unsubstituted or can be substituted by radicals such as alkyl, hydroxy, alkoxy, halo, nitro, mercapto, amino, substituted amino, cyano, carboxy, sulfoamino, carbamoyl, carbamoyloxy, sulfonyl, sulfinyl, sulfamoyl, azido, amino, substituted amino, carboxamido or N-substituted carboxamido; and

B₃ is hydrogen or B₁. Representative examples of such groups are C₁₋₆ alkyl especially methyl, ethyl or t-butyl, allyl, 3-butenyl, methoxyethyl, benzyl, p-carbomethoxybenzyl, m-carbomethoxybenzyl, p-aminosulfonylbenzyl, m-fluorobenzyl, o,p-dinitrobenzyl, o,p-dichlorobenzyl, p-methylbenzyl, m-methoxybenzyl, o-methylthiobenzyl, benzhydryl, CH₂ CH₂ CH₂ COOCH₃ --CH₂ COOC₂ H₅, and the like.

Preferably B₁ and B₂ independently are substituted or unsubstituted

(1) aralkyl;

(2) aryl;

(3) straight or branched loweralkyl;

(4) straight or branched loweralkenyl;

(5) cycloalkyl;

(6) alkanoyloxyloweralkyl;

(7) alkanoylloweralkyl;

(8) alkoxyloweralkyl; or

(9) haloalkyl; and

B₃ is H or B₁.

Even more preferably, B₁ and B₂ independently are substituted or unsubstituted

(1) benzyl;

(2) ethyl;

(3) t-butyl;

(4) --CH₂ CH₂ CH=CH₂ or --CH₂ CH=C(CH₃)₂ ;

(5) --CH₂ CH₂ CH₂ COOt-Bu;

(6) alkanoyloxymethyl; or

(7) alkanoylmethyl.

B₃ is H or B₁ ; Q in formula (I) represents

(1) hydrogen;

(2) C₁₋₆ alkyl especially methyl, ethyl, isopropyl, n-pentyl or n-hexyl;

(3) halo C₁₋₆ alkyl especially chloro or fluoro C₁₋ 6 alkyl; or

(4) hydroxy C₁₋₆ alkyl;

(5) methylene or substituted methylene especially C₁₋₆ alkylmethylene, unsubstituted or substituted phenylmethylene, phenylthiomethylene, phenylsulfinylmethylene or phenylsulfonylmethylene;

(6) C₁₋₆ alkoxy C₁₋₆ alkyl;

(7) unsubstituted or substituted benzyl; or

(8) unsubstituted or substituted phenylthio C₁₋₆ alkyl, phenylsulfonyl C₁₋₆ alkyl;

(9) unsubstituted or substituted phenoxy C₁₋₆ alkyl or

(10) unsubstituted or substituted phenylamino C₁₋₆ alkyl

Preferably, Q is

(1) hydrogen;

(2) C₁₋₆ alkyl;

(3) substituted or unsubstituted methylene;

(4) unsubstituted or substituted phenylthio C₁₋₆ alkyl or phenylsulfonyl C₁₋₆ alkyl.

Even more preferably, Q is

(1) hydrogen;

(2) methyl, ethyl or i- or n-propyl;

(3) methylene; or

(4) phenylthiomethyl or phenylsulfonyl methyl.

The cephalosporin esters of structural formula (I) where OB₁ is other than hydroxy can be prepared from the corresponding acid according to conventional methods of esterification. For example,

(1) A compound of formula (I) is treated with a lower alkanol, a substituted or unsubstituted benzyl alcohol, or a substituted or unsubstituted benzhydrol (diphenylmethanol) in the presence of a catalyst such as sulfuric acid, hydrochloric acid and any one or a combination of the acid illustrated below in Table I:

                  TABLE I     ______________________________________     Catalysts for Esterification     ______________________________________     (1)     Hydrochloric acid or hydrobromic acid     (2)     Sulfuric acid     (3)     C.sub.1-3 alkanoic acid e.g. acetic acid     (4)     Phosphoric acid     (5)     Trifluoroacetic acid or anhydride     (6)     Trichloroacetic acid     (7)     p-Toluenesulfonic acid or other arylsulfonic             acids     (8)     Acidic ion-exchange resins with calcium             sulfate     (9)     Polymer-protected aluminum chloride, e.g.,             a complex between anhydrous aluminum             chloride and polystyrene-divinyl benzene             copolymer diphenylphosphitepyridine     (10)    A Lewis acid such as boron trifluoride     (11)    Aromatic sulfonylchloride-pyridine, e.g.,             p-toluenesulfonylchloride     (12)    triphenylphosphine ditriflate     (13)    dicyclohexylcarbodiimide (DCCD)     (14)    β-trichloromethyl-β-pro-piolactone     (15)    N,N'--carbonyldimidazole     (16)    triphenylphosphinediethylazodicarbonylate     (17)    6-chlorobenzensulfonyloxybenzotriazole     (18)    1-methyl-2-halopyridinium iodide-tertiary             amine (e.g., triethylamine).     ______________________________________

at from about 0° to about 150° C. with or without refluxing until the esterification is substantially complete. Optionally, a solvent may be used to facilitate the reaction. The common solvents used are benzene, toluene, xylene, sulfolane-xylene, diethylether, tetrahydrofuran, 1,2-dimethoxyethane, dioxane and the like;

(2) A compound of formula (I) is converted to an acid halide such as acid chloride or bromide via treatment with a halogenating agent such as thionyl chloride, phosphorus penta- or oxychloride followed by reaction with an appropriate alcohol; and

(3) Other methods such as alkylation of carboxylate salts (e.g., K⁺, Na⁺, Ca⁺⁺, Ag⁺, Cu⁺, tetralkylammonium-R₄ N⁺, and Hg⁺⁺ salts) of formula (I) with alkyl halides, for example, benzylchloride, benzyhydryl chloride; reaction with alkyl isoureas; treatment with diazomethane or diazophenylmethane (C₆ H₅ CHN₂); alcoholysis of anhydride derived from the cephalosporin acid corresponding to formula (I); transesterification with t-butyl esters or isopropenylacetate and the like may also be used. These methods are disclosed in Saul Patai, editor, The Chemistry of Functional Groups, Supplement B, The Chemistry of Acid Derivatives, pp. 411-436, John Wiley & Sons, Chichester-New York-Brisbane-Toronto, 1979, and are incorporated herein by reference.

Other specific synthetic schemes which are useful in preparing the compounds of formula (I) are described in copending applications Ser. Nos. 490,761 and 485,979, filed May 2, 1983 and Apr. 18, 1983 respectively, 1983. These synthetic methods are herein incorporated by reference.

This invention also relates to a method of treating inflammation in patients using a compound of Formula (I), particularly an especially preferred compound as the active constituent.

It has been found that the compounds of Formula (I) have anti-inflammatory/antidegeneration activity as shown below in Tables II to III by the effective inhibition of the proteolytic function of human granulocyte elastase.

                  TABLE II     ______________________________________      ##STR11##     R.sub.1      B              ED.sub.50     ______________________________________     OCH.sub.3    OCH.sub.3      2.5     OCOφ     OCH.sub.3      5.0     OCHO         OCH.sub.3      3.0     OCOCH.sub.2 φ                  OCH.sub.3      4.0     OCHO         OCH.sub.2 φ                                 2.0     OCH.sub.3    OCH.sub.2 φ(p-COOCH.sub.3)                                 0.3     OCH.sub.3    OCH.sub.2 COOC.sub.2 H.sub.5                                 0.4     OCH.sub.3    OCH.sub.2 CHC(CH.sub.3).sub.2                                 1.0     OCH.sub.3    O(CH.sub.2).sub.3 COOCH.sub.3                                 0.5     OCHO         OtBu           5.0     OCOCH.sub.2 φ                  OtBu           3.0     Cl           OtBu           0.5     OCH.sub.3    OtBu           3.5     ______________________________________

TABLE III

Protocol - Enzyme Assays for the Inhibition of Human Polymorphonuclear Leukocyte Elastase Via Hydrolysis of

N-t-Boc-alanyl-alanyl-prolylalanine-p-nitroanilide Reagents:

0.05M TES (N-tris[hydroxymethyl]methyl-2-amino-ethanesulfonic acid) Buffer, pH 7.5.

0.2 mM N-t-Boc-alanyl-alanyl-prolyl-alanine-p-nitroanilide (Boc-AAPAN).

To prepare substrate, the solid (m.w. 550) was first dissolved in 10.0 ml DMSO. Buffer at pH 7.5 was then added to a final volume of 100 ml.

Crude extract of human polymorphonuclear leukocytes (PMN) containing elastase activity.

Inhibitors (cephalosporin esters) to be tested dissolved in DMSO just before use.

Assay Procedure:

To 1.0 ml of 0.2 mM Boc-AAPAN in a cuvette, 0.01-0.1 ml of DMSO with or without inhibitor was added. After mixing, a measurement was taken at 410 mμ to detect any spontaneous hydrolysis due to presence of test compound. 0.05 Milliliters of PMN extract was then added and the ΔOD/min at 410 mμ was measured and recorded. Beckman model 35 spectrophotometer was used.

Results:

Results were reported as ED₅₀, i.e., effective dosage in micrograms per milliliter (μg/ml) for 50% inhibition of the enzyme activity 2 minutes after zero time.

Comments:

The elastase activity in the crude PMN extract may vary from one preparation to another. A control of each new batch is run, and the volume added in the assay procedure is adjusted according to activity.

Accordingly, the compounds of Formula (I) can be used to reduce inflammation and relieve pain in diseases such as emphysema, rheumatoid arthritis, osteoarthritis, gout, bronchial inflammation, infectious arthritis, rheumatic fever and the like.

For treatment of inflammation, fever or pain, the compounds of Formula (I) may be administered orally, topically, parenterally, by inhalation spray or rectally in dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles. The term parenteral as used herein includes subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques. In addition to the treatment of warm-blooded animals such as mice, rats, horses, dogs, cats, etc., the compounds of the invention are effective in the treatment of humans.

The pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparation. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, maize starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate may be employed.

Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or koalin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyxyethylene sorbitan monooleate. The said aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl, p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.

Oily suspension may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an antioxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oils, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan mono-oleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening and flavoring agents.

Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents. The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleagenous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example as a solution in 1,3-butane diol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono-or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.

The compounds of Formula (I) may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.

For topical use, creams, ointments, jellies, solutions or suspensions, etc., containing the anti-inflammatory agents are employed.

Dosage levels of the order to 0.2 mg to 140 mg per kilogram of body weight per day are useful in the treatment of the above-indicated conditions (10 mg to 7 gms. per patient per day). For example, inflammation is effectively treated and anti-pyretic and analgesic activity manifested by the administration from about 0.5 to 50 mg of the compound per kilogram of body weight per day (25 mg to 3.5 gms per patient per day). Advantageously, from about 2 mg to about 20 mg per kilogram of body weight per daily dosage produces highly effective results (50 mg to 1 gm per patient per day).

The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. For example, a formulation intended for the oral administration of humans may contain from 5 mg to 5 gm of active agent compounded with an appropriate and convenient amount of carrier material which may vary from about 5 to about 95 percent of the total composition. Dosage unit forms will generally contain between from about 25 mg to about 500 mg of active ingredient.

It will be understood, however, that the specific dose level for any particular patient will depend upon a variety of factors including the activity of the specific compound employed, the age, body weight, general health, sex, diet, time of administration, route of administration, rate of excretion, drug combination and the severity of the particular disease undergoing therapy.

EXAMPLE 1 t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylate

Step A: Preparation of t-Butyl 3-acetyloxymethyl-7-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Into a two-liter Erlenmeyer flask is placed a solution of 7-ACA tert-butyl ester (7-ACA═3-acetyloxymethyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate (22.22 g; 0.067 mol) in CH₂ Cl₂ (500 ml). To this solution was added a mixture of sodium nitrite (4.68 g, 0.067 mol) in water (500 ml). The resulting two-phase mixture was cooled in an ice bath, and then 2N aqueous H₂ SO₄ (51 ml) was added dropwise over 30 minutes with vigorous stirring. Stirring was continued for one hour at 0°, then the layers were separated and the aqueous layer was washed with methylene chloride (200 ml). The organic layers were combined, washed with brine (250 ml), dried over MgSO₄, and filtered to give a yellow solution of the diazo product which is used directly in the next reaction.

Step B: Preparation of t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

The solution of t-butyl 3-acetyloxymethyl-7α-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate was cooled in an ice bath, and methanol (525 ml) was added. To this chilled mixture was added Rhodium (II) acetate dimer (210 mg), and the reaction mixture was stirred for 45 minutes, during which time the color changes from yellow to green-brown. The reaction mixture was filtered through silica gel, concentrated and dried in vacuo to give a dark red oil which was then purified by preparative high-pressure liquid chromatography to give 9.62 g (41.4%) of t-butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a yellow oil.

EXAMPLE 2 t-Butyl 3-acetyloxymethyl-7α-formyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Step A: Preparation of t-Butyl 3-acetyloxymethyl-7α-hydroxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Crude t-butyl 3-acetyloxymethyl-7-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate was taken up in 400 ml of acetone and 400 ml of water containing 80 ml of 1N perchloric acid is added at room temperature. The reaction was stirred for 3 hours (or until nitrogen evolution ceases) and was then diluted with water and extracted twice with methylene chloride. The organic phases were washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel with 30% ethyl acetate-hexane to give 2.75 g (13%) of t-butyl 3-acetyloxymethyl-7α-hydroxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a white solid, NMR (CDCl₃): δ0.53 (s, 9), 2.07 (s, 3), 3.35 (ABq, 2, 18 Hz), 4.5-5.0 (m, 4).

Step B: Preparation of t-Butyl 3-acetyloxymethyl-7α-formyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a solution of 1.5 g (4.6 mmols) of t-butyl 3-acetyloxymethyl-7α-hydroxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate in 50 ml of methylene chloride at 0° C. was added 1.5 ml of acetic-formic anhydride reagent (prepared by cooling 2 volumes of acetic anhydride to 0° C., slowly adding 1 volume of 96% formic acid, heating at 50° for 15 minutes and cooling) followed by 1.2 ml of pyridine. The reaction was allowed to warm to room temperature, stirred for 2 hours and then quenched by addition of ice water. The layers were separated and the organic layer was washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated in vacuo. The residue was triturated with 30% ethyl acetate-hexane to give 700 mg (43%) of t-butyl 3-acetyloxymethyl-7α-formyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene- 2-carboxylate, NMR (CDCl₃) δ1.53 (s, 9), 2.03 (s, 3), 3.40 (AB q, 2, 17 Hz), 4.67 (d, 1, 2 Hz) 4.78 (ABq, 2, 13 Hz), 5.49 (br d, 1, 2 Hz), 7.99 (s, 1).

EXAMPLE 3 t-Butyl 3-acetyloxymethyl-7α-acetyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a solution of 240 mg (0.73 mmoles) of t-butyl 3-acetyloxymethyl-7α-hydroxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate in 10 ml of methylene chloride at 0° C. was added 85 mg (1.1 mmols) of acetyl chloride and 90 mg (1.1 mmols) of pyridine. The ice bath was removed and the reaction was stirred at room temperature for 3 hours. The reaction was then poured into ice water and the layers separated. The organic layer was washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride, dried over sodium sulfate, and evaporated. Chromatography on silica gel with 30% ethyl acetate-hexane and trituration with hexane gave 100 mg (37%) of t-butyl 3-acetyloxymethyl-7α-acetyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a white solid, m.p. 94°-95° C. with decomposition.

EXAMPLE 4 Methyl 3-chloro-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Step A: Preparation of Methyl 3-ethoxythiaoxothiomethyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a vigorously stirred suspension of 8 g (23.9 mmols) of 3-ethoxythiaoxothiomethyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid in 300 ml of methanol was slowly added a solution of diazomethane in ethyl ether until most of the solid dissolves. The excess diazomethane was quenched after 5 minutes by addition of acetic acid. The reaction was then poured into ice water and extracted twice with ethyl acetate/ethyl ether (1:1). The organic layers were washed with water and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated in vacuo.

The residue was flash chromatographed eluting with a solvent gradient of 50 to 70% ethyl acetate-hexane to give 4.5 g (54%) of methyl 3-ethoxythiaoxothiomethyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a white solid, NMR (CDCl₃) δ1.40 (t, 3, 7 Hz), 1.73 (br s, 1) 3.53 (ABq, Z, 19 Hz), 3.87 (s, 3), 4.30 (ABq, 2, 13 Hz), 4.5-5.0 (m, 4).

Step B: Preparation of Methyl 3-ethoxythiaoxothiomethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Following substantially the same procedures as described in Example 1, Steps A and B, 4.5 g (12.9 mmoles) of methyl 3-ethoxythiaoxothiomethyl-7-α-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate were converted to 1.2 g (26%) of methyl 3-ethoxythiaoxothiomethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a yellowish solid, NMR (CDCl₃) 1.38 (t, 3, 7 Hz), 3.43 (ABq, 2, 18 Hz), 3.51 (s, 3), 3.86 (s, 3H), 4.22 (HBq, 2, 13 Hz), 4.3-4.7 (m, 4).

Step C: Preparation of Methyl 3-methylene-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]octane-2-carboxylate

To a suspension of 8 g of Raney nickel in 70 ml of water under nitrogen was added 1.2 g (3.3 mmoles) of methyl 3-ethoxythiaoxothiamethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2carboxylate in 70 ml of ethanol. The mixture was hydrogenated at 40 psi of hydrogen in a Parr shaker at room temperature for 16 hours. The catalyst was then removed by filtration and the filtrate was diluted with water and extracted twice with ethyl acetate. The organic layers were washed with water and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated in vacuo. The residue was flash chromatographed eluting with a solvent gradient of 30 to 40% ethyl acetate-hexane to give 500 mg (62%) of methyl 3-methylene-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]octane-2-carboxylate as a colorless oil, NMR (CDCl₃) δ3.33 (ABq, 2, 14 Hz), 3.56 (s, 3), 3.73 (s, 3), 4.40 (br s, 1), 5.0-5.3 (m, 4).

Step D: Preparation of Methyl 3-hydroxy-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution of 200 mg (0.82 mmols) of methyl 3-methylene-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]octane-2-carboxylate in 15 ml of methylene chloride was cooled to -70° C. in a dry ice-acetone bath. Ozone was bubbled through the solution until the first sign of blue coloration was noticed. Nitrogen was then bubbled through to flush out the excess ozone, 2 g of sodium bisulfite were added and the suspension was vigorously stirred at 0° C. for 30 minutes.

The reaction was filtered and the filtrate was evaporated in vacuo to give crude product which was used directly in the next step.

Step E: Preparation of Methyl 3-chloro-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

The crude methyl 3-hydroxy-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate (approximately 0.82 mmols) was taken up in 10 ml of dimethylformamide and slowly added to a solution of 680 mg (3.3 mmols) of phosphorous pentachloride in 10 ml of N,N-dimethylformamide at -60° C. (prepared by stirring at -10° C. for 15 minutes, then cooling to -60° C.). The solution was stirred at -60° C. for 30 minutes, then at -10° C. for 90 minutes before it was quenched by pouring into water/ethyl acetate. The organic layer was washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated in vacuo to give a crude residue of methyl 3-chloro-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate.

EXAMPLE 5 Methyl 3-tosyloxy-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution of 450 mg of crude methyl 3-hydroxy-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate in 5 ml of pyridine was stirred with 470 mg (2.4 mmols) of tosyl chloride at 0° C. for 3 hours. The reaction mixture was poured into ice water and extracted twice with ethyl acetate. The organic layers were washed twice with dilute aqueous hydrochloric acid and saturated aqueous sodium chloride, dried over sodium sulfate and evaporated in vacuo to give a crude residue of methyl 3-tosyloxy-7α-methoxy-8-oxo-5-thio-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate.

EXAMPLE 6 t-Butyl 3-acetyloxymethyl-7α-fluoro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

t-Butyl 3-acetyloxymethyl-7-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate was prepared from 10 mmoles 7-amino derivatives in the same manner as described in Step A, Example 1, and taken up in 25 ml dry methylene chloride. To it with stirring was added dropwise over 30 seconds 0.60 ml 70% HF in pyridine. The mixture was stirred 2.5 minutes more and then washed with aq K₂ HOP₄, water, aq H₃ PO₄ and brine. It was dried with MgSO₄, filtered and chromatographed on 16 g silica gel with 1:1 hexane-ethyl acetate, affording 183 mg of t-butyl 3-acetyloxymethyl-7α-fluoro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate. IR(μ): 5.57, 5.76. NMR CDCl₃) 1.54 s, t-Bu; 2.08 s, Ac; 3.34 d of d, J=18, 1.9 Hz, and 3.58 d of d, J=18, 0.8 Hz, SCH₂ ; 4.75 d, J=13 Hz and 4.97 d, J=13 Hz, CH₂ OAc; 4.90 d of d, J=9, 1.6 Hz, CHS; 5.32 d of d, J=54, 1.6 Hz, CHF. MS: 332.

EXAMPLE 7 t-Butyl 3-acetyloxymethyl-7α-chloro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Following the same procedure as described in Step A, Example 1, 7-ACA t-butyl ester was diazotized to t-Butyl 3-acetyloxymethyl-7-diazo-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate which was taken up into 2 ml EtOH, and treated with 0.1 ml aq HCl. There was an instantaneous vigorous effervescence. After 15 seconds, aq K₂ HPO₄ and methylene chloride were added. The methylene chloride layer was separated, washed with aq H₃ PO₄ and brine, dried with MgSO₄, filtered and chromatographed by PLC on silica gel, eluting with 25:1 CHCl₃ -EtOAc, to provide 61 mg pure t-Butyl 3-acetyloxymethyl-7α-chloro-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate. NMR (CDCl₃) 1.55 s, t-bu; 2.10 s, Ac; 3.40 d, 3.59 d, J=18 Hz, SCH₂ ; 4.79 d, 5.03 d, J=13 Hz, CH₂ OAc; 4.70 d, J=1.5 Hz, CHS; 4.78 d, J=1.5 Hz, CHCl. MS: 291 Cl₁, 231 Cl₁.

EXAMPLE 8 t-Butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate

Step A: Preparation of t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate

In a 200 ml round bottom flask equipped with a magnetic stirrer were placed t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thio-2-azabicyclo[4.2.0]oct-2-ene-2-carboxylate (7.46 g, 21.7 mmol) chloroform (90 ml) and triethylamine (3.3 ml, 23.6 mmol). The mixture was then heated to reflux for three hours. ¹ H NMR analysis of an aliquot shows that there was a mixture of 3-ene and 2-ene isomers in the approximate ratio of 3:1. The reaction mixture was then evaporated and the brown residue was dried in vacuo. The mixture was then purified by preparative HPLC on a Waters Prep 500 using two silica gel columns in series and hexane:ethyl acetate (3:1) as eluent. The forecut of the partially resolved material was taken and evaporated to give 2.41 g (32%) of pure t-Butyl 3-acetyloxymethyl- 7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate isomer as a yellow oil. NMR (CDCl₃): δ6.45 (2-H, br, s), 5.05 (4-H, br s), 4.90 (5-H, d, J=2), 4.65 (6-H, d, J=2), 4.60 (CCH₂ OAc, t, J=13 Hz), 3.52 (OCH₃, s), 203 (O₂ CCH₃, s), 1.50 (s, OC(CH₃)₃).

Collection of the remainder of the material and evaporation yielded 3.66 g (49%) of a 1:1 mixture of 2-ene and 3-ene isomers as a yellow oil which may be reused in the reaction.

Step B: Preparation of t-Butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo [4.2.0]oct-3-ene-2-carboxylate

To a solution of 8.88 g (25.9 mmol) of t-butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate in isopropanol (100 ml) was added Ti(O-iPr)₄ (5.4 ml). The reaction mixture was heated to reflux under N₂ and monitored by TLC [silica gel using hexane:ethyl acetate (1:1); starting material R_(f) 0.75, product R_(f) 0.5] until the starting material had just disappeared. The reaction was concentrated and the residue was dissolved in ethyl acetate and washed with 1N aqueous H₃ PO₄ (50 ml). The aqueous layer was then backwashed with ethyl acetate (50 ml) and the organic layers were combined, washed with water (50 ml) and brine (50 ml). The organic layer was dried over MgSO₄ and concentrated to give a yellow oil which was purified using a Waters Prep 500 with hexane:ethyl acetate (2:1) as eluent to give 4.76 g (61%) of a light yellow oil which on standing crystallizes to t-butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate. carboxylate. ¹ H NMR (CDCl₃): δ6.32 (2-H, m); 5.02 (4-H, s); 4.99 (6-H, J=1 Hz), 4.60 (7-H, d J=1 Hz); 4.22 (CCH₂ OH, br s); 3.53 (OCH₃, s); 2.60 (OH, br exch.); 1.50 (C(C₃)₄, s).

EXAMPLE 9 t-Butyl 3-(3-[hydroxycarbonyl]propanoyloxymethyl)-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate

A mixture of t-Butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo [4.2.0]oct-3-ene-2-carboxylate (602 mg, 2.0 mmol) and succinic anhydride (300 mg, 3.0 mmol) were dissolved in dry tetrahydrofuran (4 ml) under nitrogen at room temperature, then 4-[N,N-dimethylamino]pyridine (300 mg, 2.5 mmol) was added with stirring. A solid began to separate out shortly after mixing. The mixture was allowed to stir 15 hours, then saturated aqueous sodium bicarbonate (10 ml) was added, and the mixture was extracted with ether (2×20 ml). The combined ether extracts were washed with sat. aq NaHCO₃ (10 ml), then the aqueous extracts were combined and acidified to pH 2.5 (using 1.0 M.H₃ PO₄), the resulting cloudy solution was extracted with ethyl acetate (2×30 ml), then the organic layers were combined and washed with saturated brine (25 ml) and dried over Na₂ SO₄. The solvent was removed in vacuo to give t-butyl 3-hydroxycarbonylethylcarbonyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate a yellow oil.

EXAMPLE 10 t-Butyl 3-hydroxycarbonylmethylaminocarbonyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate

To a solution of t-butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate (602 mg, 2.0 mmol) in methylene chloride (5 ml) was added N,N'-carbonyldiimidazole (324 mg, 2.0 mmol). The resulting solution was stirred at room temperature for thirty minutes, then the solvent was removed in vacuo and the residue was dissolved in N,N-dimethylformamide (5 ml). Then glycine p-methoxybenzylester hydrochloride (693 mg, 3.0 mmol) and 4-(N,N-dimethylamino)pyridine (366 mg, 3.0 mmol) were added, and the resulting mixture was stirred for 18 hours. The reaction mixture was then poured into water (30 ml) and extracted with ethyl acetate (2×30 ml). The combined organic layers were washed with water (20 ml) and saturated brine (20 ml), then dried over sodium sulfate, and the solvent was removed to give a residue which was purified by chromatography (4×[20 cm×20 cm] 2000μ silica gel GF plates, developed in ethyl acetate/hexane [1/1]). The bands at R_(f) 0.55 were removed and eluted with ethyl acetate to produce 508 mg (51%) of t-butyl 3-(p-methoxybenzyloxy)carbonylmethylaminocarbonyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicylco[4.2.0]oct-3-ene-2-carboxylate. ¹ H NMR (CDCl₃): δ7.25-6.85 (C₆ H₄ OCH₃, d, d, J=9 Hz); 6.40 (C═C(H)S--, br. s); 5.40 (═NH, br, s); 5.18 (--C₆ H₄ --CH₂ --, s); 5.05 (--CH--CH═CHS--, s); 4.90 (C-6H, d, J=2 Hz); 4.70 (C-7H, d, J=Hz); 4.65 (C--3--CH₂, t, J=12 Hz); 3.95 (--HN--CH₂ CO--, d, J=6 Hz); 3.80 (--C₆ H₄ --OCH₃, s); 3.55 (C--7--OCH₃, s); 1.55 [--COO--C(CH₃)₃ ].

EXAMPLE 11 t-Butyl 3-formyl-7α-methoxy-8-oxo-5-thia-1azabicyclo[4.2.0]-oct-3-ene-2-carboxylate

To a 100 ml recovery flask under nitrogen was added solution of t-butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo [4.2.0]oct-3-ene-2-carboxylate (300 mg 1.0 mmol) in acetone (26 ml-freshly distilled from Jones' Reagent). The solution was then cooled to 0°, and Jones Reagent (1.0 mmol, 372 μl of a 2.7 M solution) was added slowly with stirring. There was an immediate color change from yellow to green with precipitate formation. After the addition was complete, stirring was continued for ten minutes, then it was poured into water (100 ml) and stirred. The resulting green solution was extracted with ethyl acetate (4×30 ml), and the combined organic extracts were washed with brine, then dried with sodium sulfate. The solvent was removed to give a yellow oil (264 mg) which was purified by chromatography (2000μ silica gel GF prep plate [20×20 cm] using ethyl acetate:hexane (1:1) as eluent). The band of R.sub. f 0.5 was removed to give 214 mg (72%) of t-butyl 3-formyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate as a clear oil which solidified on cooling. ¹ H NMR (CDCl₃): δ9.40 (--CHO, s); 7.55 (C₂ -H, d, J=1 Hz); 5.30 (C₆ or C₇ -H, d, J=1); 5.08 (C₄ -H, d, J=1); 4.65 (C₆ or C₇ -H, d, J=1); 3.55 (C₇ (OCH₃), s); 1.55 (CO₂ C(CH₃)₃ m s).

EXAMPLE 12 t-Butyl 3-chloromethyl-7α-methoxy-8-oxo-5-thia-1azabicyclo[4.2.0]oct-3-ene-2-carboxylate

To a solution of 0.9 g (3 mmol) of t-butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate in 20 ml of tetrahydrofuran was added 1 ml of pyridine. Thionyl chloride (0.5 ml) was added dropwise over 5 min. After stirring the reaction mixture for 0.5 hours, it was poured into ice-cold water and extracted with ethyl acetate. The combined extract was washed with 7% sodium bicarbonate solution, brine and dried over sodium sulfate. The concentrated filtrate was flash chromatographed with 10% ethyl acetate-hexane to yield 0.626 g (65%) yield of t-butyl 3-chloromethyl-7α-methoxy-8-oxo-5-thia-1-azacyclo[4.2.0]oct-3-ene-2-carboxylate as a pale yellow solid. m.p. 85°.

EXAMPLE 13 t-Butyl 3-methoxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate

A solution of 30 mg (0.09 mmol) of t-butyl 3-chloromethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo 4.2.0]oct-3-ene-2-carboxylate in 1 ml of methanol was stirred at room temperature for 16 hours. The solution was concentrated in vacuo and the residue was chromatographed on a short silica gel column with 20% ethyl acetate-hexane to obtain 21 mg t-butyl 3-methoxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct-3-ene-2-carboxylate.NMR (CDCl₃); δ3.25 (s, 1.5) 3.39 (s, 1.5), 6.23 (bs, 0.5).

EXAMPLE 14 t-Butyl 3-methyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a solution of 5 g (24.6 mmol) of t-butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate in 100 ml of ethanol was added 15 g of 10% palladium on carbon under a nitrogen atmosphere. The solution was hydrogeneated on a Parr appartus for 3 hr. The reaction mix was filtered and the catalyst was thoroughly washed with warm methanol. The filtrate and washings were combined and concentrated in vacuo. The residue was flash-chromatographed using 20% ethyl acetate-hexane to obtain 1.97 g (47% yield) of t-butyl 3-methyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate. NMR (CDCl₃): δ1.53 (s, 9), 2.01 (s, 3), 3.27 (ABq, 2, 18 Hz), 3.52 (s, 3), 4.40 (d, 1, 2 Hz), 4.6 (d, 1, 2 Hz).

EXAMPLE 15 t-Butyl 3-methyl- 7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a solution of 2.5 ml of sulfuric acid in 25 ml of dioxane were added, with ice cooling, 2.5 g (11.7 mmol) of 3-methyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 15 ml of isobutylene. The mixture was sealed in a pressure bottle and stirred for 2 hours at room temperature. The contents of the bottle were poured into 300 ml of ice-cold water containing 15 g of sodium bicarbonate. The solution was extracted with ethyl acetate. The combined ethyl acetate extract was washed with brine and dried over sodium sulfate. Evaporation of the filtrate in vacuo gave 1.2 g (38% yield) of t-butyl 3-methyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate. NMR (CDCl₃): δ1.51 (s, 9), 1.78 (bs, 2), 2.05 (s, 3), 3.3 (ABq, 2, 18 Hz), 4.64 (d, 1, 4 Hz), 4.85 (d, 1, 4 Hz).

EXAMPLE 16 m-Methoxycarbonylbenzyl-3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Step A: Preparation of N,N'-diisopropyl-O-(m-methoxycarbonylbenzyl)-isourea

A mixture of 4.75 g (28.6 mmols) of m-methoxycarbonylbenzyl alcohol and 3.6 g (28.6 mmols) of N,N'-diisopropylcarbodiimide was stirred with 50 mg (0.51 mmols) of cuprous chloride at room temperature for 24 hours. The reaction was then diluted with 10 ml of hexane and eluted through a short column of neutral alumina with 20% ethyl acetate-hexane to give 8.0 g (96%) of N,N'-diisopropyl-O-(m-methoxycarbonylbenzyl)-isourea as a colorless oil.

Step B: Preparation of m-methoxycarbonylbenzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution of 1.0 g (3.4 mmole) of 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 1.0 g (3.4 mmole) of N,N'-diisopropyl-O-(p-methoxycarbonylbenzyl)-isourea in 2.0 ml of tetrahydrofuran (THF) was stirred for 24 hours at room temperature. The reaction was then cooled to -10° C., filtered and concentrated in vacuo. The product was purified by flash chromatography using a solvent gradient of 35 to 40% ethyl acetate-hexane to give 300 mg (20%) of m-methoxycarbonylbenzyl-3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as an oil, NMR (CDCl₃); δ2.04 (s, 3), 3.40 (ABq, 2, 18 Hz) 3.50 (s, 3), 3.87 (s, 3), 4.47 (d, 1, 2 Hz), 4.63 (d, 2, 2 Hz), 4.78 (ABq, 2, 13 Hz), 5.27 (ABq, 2, 13 Hz), 7.2-7.6 (m, 2), 7.7-8.0 (m, 2).

Following substantially the same procedure as described above but substituting for the N,N'-diisopropyl-O-(m-methoxycarbonylbenzyl)-isourea used therein N,N'-diisopropyl-O-(p-(p-methoxybenzyloxy)carbonylbenzyl)-isourea, there was prepared p-(p-methoxybenzyloxy)carbonylbenzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as an oil, NMR (CDCl₃) δ2.02 (s, 3), 3.42 (ABq, 2, 19 Hz), 3.53 (s, 3), 3.73 (s, 3), 4.44 (d, 1, 2 Hz), 4.62 (d, 1, 2 Hz), 4.80 (ABq, 2, 13 Hz), 5.27 (ABq, 2, 13 Hz), 6.7-8.1 (m, 8).

EXAMPLE 17 Ethoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution of 1.0 g (3.5 mmols) of 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 4 ml of ethyl diazoacetate in 25 ml of methylene chloride was stirred with 10 mg of rhodium (II) acetate dimer at 35° C. for 30 minutes. The reaction was then concentrated in vacuo and the residue was purified by flash chromatography on silica gel eluting with 40-50% ethyl acetate-hexane. The fractions containing the product were combined, evaporated and rechromatographed using 10% ethyl acetate-methylene chloride as eluant to give 250 mg (34%) of ethoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate, NMR (CDCl₃); δ1.27 (t, 3, 7 Hz), 2.06 (s, 3), 3.43 (ABq, 2, 19 Hz), 3.53 (s, 3), 4.20 (q, 2, 7 Hz), 4.43 (d, 1, 2 Hz), 4.63 (d, 1, 2 Hz), 4.73 (ABq, 2, 16 Hz), 4.87 (ABq, 2, 13 Hz).

EXAMPLE 18 t-Butoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution of 500 mg (1.7 mmols) 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid in 2 ml of N,N-dimethylacetamide was stirred with 300 mg (3.4 mmols) of sodium bicarbonate and 525 mg (3.4 mmoles) of t-butyl chloroacetate at room temperature for 16 hours. The reaction was diluted with water and extracted with methylene chloride. The organic layer was washed with water and saturated aqueous sodium chloride solution dried over sodium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel to give 20 mg of the t-butoxycarbonylmethyl ester as a mixture of 3-ene and 2-ene isomers of t-butoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate.

EXAMPLE 19 N-Benzyl-N-methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide

A solution of 2.0 g (7.0 mmol) of 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid in 10 ml of dioxane and 20 ml of acetone was stirred with 1.0 g (7.0 mmols) of isobutyl chloroformate and 600 μl (7.0 mmols) of pyridine at -15° C. After 20 minutes 2.5 g (21 mmoles) of N-methyl-N-benzylamine was added and the reaction is stirred at -15° C. for 1 hour, then allowed to warm to room temperature for 2 hours. The reaction was quenched with dilute hydrochloric acid and extracted into methylene chloride. The organic layer was washed with saturated aqueous sodium bicarbonate solution and saturated aqueous sodium chloride solution, dried over sodium sulfate and evaporated. The residue was chromatographed on silica gel to give 280 mg (10%) of N-benzyl-N-methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[ 4.2.0]oct-2-ene-2-carboxamide, NMR (CDCl₃); δ1.97 and 2.00 (s, 3), 2.83 and 2.90 (s, 3), 3.0 to 3.7 (m, 5), 4.3 to 4.8 (m, 6), 7.3 (br s, 5).

EXAMPLE 20 N-(t-Butoxycarbonyl)methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide

A solution of 1.0 g (3.4 mmoles) of 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid in 25 ml of methylene chloride was stirred with 1.1 g (5.1 mmole) of dicyclohexylcarbodiimide and 450 mg (3.4 mmols) of tert-butyl glycinate at room temperature for 4 hours. The reaction was concentrated in vacuo and the residue was eluted through a short column of silica gel using 50-60% ethyl acetate-hexane. The fractions containing the resulting amide were combined and evaporated. The residue was further purified by chromatography on silica gel to give 230 mg (17%) of N-(t-butoxycarbonyl)methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide, NMR (CDCl₃); 1.46 (s, 9), 2.07 (s, 3), 3.1-3.6 (m, 2), 3.50 (s, 3), 3.8-4.1 (m, 2), 4.47 (br s, 1), 4.63 (br s, 1), 4.87 (ABq, 2, 13 Hz), 7.4 (br s, 1).

EXAMPLE 21 Benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Step A: Preparation of mixtures of Benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene (and -3-ene)-2-carboxylate

Trifluoroacetic acid (5 ml) was added to 316 mg (0.92 mmol) of t-butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate with cooling in an ice bath. After stirring for 0.5 hr at 0° C., the trifluoroacetic acid was evaporated in vacuo. The residue was diluted with dichloromethane and washed with cold water and brine. The dichloromethane solution was dried over sodium sulfate. Crude 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid was obtained upon concentration of the filtrate. It was dissolved in 5 ml of tetrahydrofuran and N,N'-diisopropyl-O-benzylisourea (0.33 ml, 2.5 mmol) was added. After stirring for 80 hours the reaction mixture was poured into 7% sodium bicarbonate solution and extracted with ethyl acetate. The combined organic extract was washed with brine and dried over sodium sulfate. The concentrated filtrate was flash chromatographed using 50% ethyl acetate-hexane to yield 259 mg (77% yield) of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as a mixture of -3-ene and -2-ene- isomers. NMR (CDCl₃); δ1.96 and 1.98 (s, 3), 3.4 (ABq, 0.8, 17 Hz), 3.43 (s, 1.8), 3.47 (s, 1.2), 4.2-5.3 (m, 6.6), 6.34 (bs, 0.6), 7-7.4 (m, 5).

Step B: Preparation of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate-5-oxide

A solution of 145 mg (0.38 mmol) of a mixture of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate and 3-ene-2-carboxylate was cooled in a -78° bath as 75 mg (85%, 0.38 mmol) of m-chloroperbenzoic acid in 2 ml of CH₂ Cl₂ was added. After 25 minutes the cold bath was removed and the solution was allowed to warm to room temperature during the next 0.5 hour. The reaction mixture was poured into 7% NaHCO₃ solution containing excess Na₂ SO₃ and extracted with CH₂ Cl₂. The combined CH₂ Cl₂ extract was washed with brine and dried over Na₂ SO₄. Concentration of the filtrate furnished 144 mg (96% yield) benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylate-5-oxide. NMR (CDCl₃); δ2 (s, 3), 3.22 (d, 1, 18 Hz), 3.54 (s, 3), 3.69 (d, 1, 18 Hz), 4.36 (bs, 1), 4.56 (d, 1, 13 Hz), 4.93 (bs, 1), 5.06 (d, 1, 13 Hz), 5.17 (m, 2), 7.1-7.6 (m, 5).

Step C: Preparation of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2-ene-2-carboxylate

A solution of 144 mg (0.37 mmol) of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate-5-oxide in 5 ml of N,N-dimethylformamide was cooled in an ice bath as 190 mg (1 mmol) of SnCl₂ was added. After 1 minute acetyl chloride (1 ml) was added. The ice bath was removed after 10 minutes and the reaction mixture was stirred for 15 minutes more. The solvent was evaporated in vacuo and the residue was dissolved in ethyl acetate. The solution was washed with water and the water wash was backextracted with ethyl acetate. The combined ethyl acetate layer was washed with brine and dried over Na₂ SO₄. The concentrated filtrate was flash chromatographed with 30% ethyl acetate-hexane to obtain 106 mg (74% yield) of benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate free from the 3-ene isomer. NMR (CDCl₃); δ1.98 (s, 3), 3.4 (ABq, 2, 18 Hz), 3.51 (s, 3), 4.44 (d, 1, 2 Hz), 4.61 (d, 1, 2 Hz), 4.75 (ABq, 2, 13 Hz), 5.22 (ABq, 2, 11 Hz), 7.1-7.5 (m, 5).

EXAMPLE 22 t-Butyl 3-acetyloxymethyl-7β-formamido-8-oxo-5-thia-1azabicyclo[4.2.0]oct-2-ene-2-carboxylate

To a solution of t-butyl 3-acetyloxymethyl-7β-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate (328 mg, 1.0 mmoles) in methylene chloride (10 ml) cooled to 0° under N₂ was added acetic-formic anhydride (200 μl-prepared by the method of Fieser and Fieser). The cooling bath was removed and the mixture was stirred for one hour, then concentrated to a yellow oil. This oil was chromatographed (2×2000μ (20×20 cm) silica gel GF using ethyl acetate:hexane [1:1] as eluent). The band at R_(f) 0.6 was removed and eluted to give 234 mg (66%) of t-butyl 3-acetyloxymethyl-7β-formamido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as an oil which solidifies on standing.

EXAMPLE 23 t-Butyl 3-trifluoromethyl-7α-trifluoromethylcarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Step A: Preparation of t-Butyl N-benzylideneglycinate

To a solution of 33.61 gms of glycine t-butyl ester and 27.19 gms of benzaldehyde in 215 ml benzene was added 21.5 gms of magnesium sulfate in one portion with stirring at room temperature. The reaction was stirred 18 hours at room temperature, filtered, diluted with ether and washed with saturated sodium bicarbonate and brine. The ether solution was then dried over magnesium sulfate, concentrated and distilled to yield 48.41 gms (86%) of t-butyl N-benzylideneglycinate.

Step B: Preparation of (2R,3S) and (2S,3R)-t-Butyl 2-amino-4-bromo-3-hydroxy-3-trifluoromethylbutyrate

To a stirred solution of 18.00 gm of t-butyl N-benzylideneglycinate in 165 ml dry tetrahydrofuran at -78° under nitrogen was added 48.0 ml of a 1.69 M solution of n-butyllithium in hexane dropwise over 10 min. After stirring an additional 10 minutes, 15.68 g of 3-bromo-1,1,1-trifluoropropanone was added dropwise, and the mixture allowed to warm gradually to -20° C. before it was recooled to -78° C. and quenched by addition of 4.70 ml glacial acetic acid. The reaction was then concentrated under reduced pressure to yield a residue which was partitioned between water and ether. The organic phase was separated, water washed, dried over magnesium sulfate, filtered and evaporated. The resulting brownish oil was taken up in 165 ml methanol and treated with 13.84 gms of Girard T reagent at room temperature for 1 hour. The solution was then concentrated to dryness and the residue shaken with water and ether. The layers were separated, and the organic phase washed with water, dried over magnesium sulfate, filtered and concentrated under reduced pressure to give 22.88 gms of a yellow oil which was chromatographed on silica gel, eluting with 90:10 hexane:ethyl acetate to yield (2R,3S) and (2S,3R)-t-butyl 2-amino-4-bromo-3-hydroxy-3-trifluoromethyl-butyrate as a yellow oil. NMR (CDCl₃): δ=1.51 (s, 9H), 3.31 (bs, 3H), 3.80 (s, 2H), 3.88 (d, J=1.1 Hz, 1H).

Step C: Preparation of (2R,3S) and (2S,3R)-t-Butyl 4-bromo-3-hydroxy-2-thioformamido-3-trifluoromethyl butyrate

A solution of 11.36 gms of (2R,3S) and (2S,3R)-t-Butyl 2-amino-4-bromo-3-hydroxy-3-trifluoromethylbutyrate in 5 ml CCl₄ was combined with 3.97 gms of ethyl thionoformate and allowed to stir at room temperature for 18 hours. The reaction mixture was then concentrated under reduced pressure and purified by chromatography on silica gel using 80:20 hexane:ethyl acetate as the eluting solvent to yield 3.67 gms of (2R,3S) and (2S,3R)-t-butyl 4-bromo-3-hydroxy-2-thioformamido-3-trifluoromethylbutyrate NMR (CDCl₃): δ1.53 (s, 9H), 3.67, 3.95 (AB-q, J=12 Hz, 2H), 4.13 (d, J=3 Hz, 1H), 6.06 (d, J=9 Hz, 1H), 8.22 (d, J=6 Hz, 1H), 9.48 (d, J=6 Hz, 1H).

Step D: Preparation of (4R,5S) and (4S,5R) t-Butyl 5-hydroxy-5-trifluoromethyl-4,5-dihydro-6H-1,3-thiazine-4-carboxylate

To a solution of 3.67 gms of (2R,3S) and 2S,3R)-t-butyl 4-bromo-3-hydroxy-2-thioformamido-3-trifluoromethylbutyrate in 65 ml acetone was added 4.15 g powdered anhydrous potassium carbonate. The reaction mixture was stirred for 30 minutes at room temperature, filtered and evaporated to dryness under reduced pressure. The crude brown oil was then purified by chromatography on silica gel using 80:20 hexane:ethyl acetate as the eluting, solvent to give 0.781 gms of white solid, (4R,5S) and (4S,5R)-t-butyl-5-hydroxy-5-trifluoromethyl-4,5-dihydro-6H-1,3-thiazine-4-carboxylate (yield 27%) m.p. 126.5°-127.5° C.

NMR (CDCl₃): δ=1.55 (s, 9H), 2.93, 3.13 (AB-q, J=13.8 Hz, 2H), 4.13 (d, J=2.7 Hz, 1H), 5.33 (s, 1H), 8.25 (d-d, J=2.7, 1.2 Hz, 1H).

Step E: Preparation of t-Butyl 3-trifluoromethyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]-oct-2(or 3)-ene-2-carboxylate

Into an oven dried 3-necked round bottom flask equipped with a magnetic stirrer, addition funnel, drying tube and nitrogen inlet was weighed 0.1586 gms of a 50% mineral oil dispersion of sodium hydride under nitrogen. The sodium hydride was then washed with two 4 ml portions of hexane which were removed by pipet, then slurried in 14 ml dry tetrahydrofuran, cooled to 0° C. in an ice bath and treated with 0.8570 g (4R,5S) and (4S,5R)-t-butyl 5-hydroxy-5-trifluoromethyl-4,5-dihydro-6H-1,3-thiazine-4-carboxylate in 9.3 ml tetrahydrofuran dropwise over 5-10 minutes. The reaction was stirred an additional 15 minutes before 0.3785 g of methanesulfonyl chloride was added dropwise via syringe in 0.2 ml tetrahydrofuran. After 2 hours of stirring at 0° C., the mixture was cooled to -78° C., and 0.3344 g of triethylamine was added in one portion followed by dropwise addition of 0.3590 g neat azidoacetyl chloride. The reaction mixture was then allowed to warm slowly to room temperature over a 21/2 hour period, after which it was poured into water and extracted with ethyl acetate. The organic phase was then washed with 2N hydrochloric acid solution, saturated sodium bicarbonate solution and water. Drying over magnesium sulfate followed by filtration and removal of solvent in vacuo yields 1.349 g of yellow oil which was dissolved in 25 ml dry pyridine under nitrogen and placed in an 83° C. oil bath with stirring for 40 minutes. The solution was then cooled and poured into water-ethyl acetate. An aqueous 10% KHSO₄ solution was then added until the aqueous phase is acidic, the layers are then shaken and separated, and the ethyl acetate solution was washed with water, dried over magnesium sulfate, filtered, and evaporated under reduced pressure to give a crude brown oil which was purified by elution through 9 gms of silica gel with 300 ml dichloromethane to afford 0.8849 g (84%) of a yellow oil consisting of a variable ratio of 2-ene and 3-ene isomers t-butyl 3-trifluoromethyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2(or3)-ene-2-carboxylate (CDCl₃): δ=1.57 (s, 9H), 3.33, 3.58 (AB-q, J=17.7 Hz, 2H), 4.60, 4.64 (AB-q, J=2.3 Hz, 2H) (spectrum of pure 2-ene-isomer).

Step F: Preparation of t-butyl 3-trifluoromethyl-7α-amino-8-oxo-5-thia-azabicyclo[4.2.0]oct-2(or 3)-ene-2-carboxylate

A solution containing 9.3 mgs of t-butyl 3-trifluoromethyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2(or 3)-ene-2-carboxylate and 5.5 mgs of platinum oxide in 3 ml of ethyl acetate was shaken for 1 hour under 35 psi hydrogen in a Parr shaker. A second portion of 5.1 mg of platinum oxide was then added, and the reaction was shaken another 30 minutes before it was judged complete by thin layer chromatography, filtered through celite and concentrated to give 8.3 gms (96%) of t-butyl 3-trifluoromethyl-7α-amino-8-oxo-5-thia-azabicyclo[4.2.0]oct-2(or 3)-ene-2-carboxylate as a dark residue.

EXAMPLE 24 p-Methoxybenzyl 3-methyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

A solution containing 3.42 grams of p-methoxybenzyl 5-methyl-6H-1,3-thiazine-4-carboxylate in 120 ml of dichloromethane was cooled in a dry ice-acetone bath. To the above stirred solution was then added 1.35 gms of triethylamine in one portion, followed by 1.59 gms of azidoacetyl chloride in 20 ml of dichloromethane dropwise over 5 minutes. Following the additions, the reaction mixture was allowed to remain in the cooling bath to come to room temperature overnight. After stirring 18 hours, the reaction mixture was washed with two 200 ml portions of water, dried over magnesium sulfate, filtered, concentrated and the residue purified by chromatography on silica gel using an 80:20 hexane:ethyl acetate mixture as the eluting solvent. Yield=2.89 gms (60%) of p-methoxybenzyl 3-methyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate as amber oil. NMR (CDCl₃): δ=2.06 (s, 3H), 3.08, 3.45 (AB-q, J=17 Hz, 2H), 3.77 (s, 3H), 4.40 (d, J=2 Hz, 1H), 4.50 (d, J=2 Hz, 1H), 5.05, 5.21 (AB-q, J=11 Hz, 2H), 7.02 (m, 4H). 

What is claimed is:
 1. A pharmaceutical composition for treating elastase-mediated conditions in a mammalian species comprising a non-toxic pharmaceutical carrier and an effective amount of a compound of structural formula: ##STR12## wherein M is:(1) trifluoromethyl; (2) chloro or fluoro; (3) --COOH; (4) --CHO; (5) tosyloxy; or (6) --CH₂ A wherein A represents(a) hydrogen; (b) halo; (c) hydroxy; (d) C₁₋₆ alkoxy; (e) phenyloxy; (f) phenyl C₁₋₆ alkoxy; (g) unsubstituted or substituted mercapto of formula SR₅ wherein R₅ is H, C₁₋₆ alkyl, phenyl, benzyl, C₁₋₆ alkenyl, (h) --SCOR, --SCOOR or SCSOR wherein R is H or C₁₋₆ alkyl; (i) C₁₋₆ alkanoyloxy, benzylcarboxyloxy or phenylcarbonyloxy; (j) a substituted or unsubstituted amino or amido group selected from a group consisting of --NH₂, --CONHR, --CON(R)₂, --NHR, and --N(R)₂ ; (k) 3-(hydroxycarbonyl)propanoyloxy; (l) hydroxycarbonylmethylaminocarbonyloxy ##STR13## R₁ is (a) hydrogen; (b) OR'₁ wherein R'₁ is C₁₋₆ alkyl, phenyl or phenyl C₁₋₆ alkyl; ##STR14## where R represents H, C₁₋₆ alkyl, phenyl, benzyl, or C₁₋₆ alkylamino; (c) C₁₋₆ alkyl, phenyl or phenyl C₁₋₆ alkyl; (d) halo; B is OB₁ or NB₂ B₃ wherein B₁ and B₂ independently are:(a) straight or branched chain alkyl having from 1 to 6 carbon atoms; (b) phenyl; (c) cycloalkyl having from 3 to 8 carbon atoms; (d) alkenyl having from 2 to 8 carbon atoms; (e) cycloalkenyl having from 5 to 8 carbon atoms; (f) alkynyl having from 2 to 8 carbon atoms; (g) alkoxy alkyl having from 2 to 10 carbon atoms; (h) phenyl C₁₋₆ alkyl or C₁₋₆ alkylphenyl; (i) C₂₋₈ alkenylalkyl; (j) C₂₋₈ alkanoylalkyl; (k) C₂₋₈ alkanoyloxyalkyl; (l) C₁₋₆ alkoxycarboxylC₁₋₆ alkyl;the above groups (a)-(l) being unsubstituted or substituted by radicals such as alkyl, hydroxy, alkoxy, halo, nitro, mercapto, amino, substituted mono or diC₁₋₆ alkyl amino, cyano, carboxy, --SO₂ NH₂, carbamoyl, carbamoyloxy, alkylsulfonyl, alkylsulfinyl, sulfamoyl, azido, carboxamido or N-substituted carboxamido; B₃ is B₁ or hydrogen; and Q is(1) hydrogen; (2) C₁₋₆ alkyl; (3) haloC₁₋₆ alkyl; (4) hydroxy C₁₋₆ alkyl; (5) C₁₋₆ alkyl methylene, phenylmethylene, or phenylthiomethylene; (6) C₁₋₆ alkoxy C₁₋₆ alkyl; (7) benzyl; (8) phenylthio C₁₋₆ alkyl, phenylsulfinyl C₁₋₆ alkyl or phenylsulfonyl C₁₋₆ alkyl; (9) phenoxy C₁₋₆ alkyl; or (10) phenylamino C₁₋₆ alkyl.
 2. The composition of claim 1 wherein:M is(1) trifluoromethyl; (2) chloro or fluoro; (3) formyl; (4) tosyloxy; (5) --CH₂ A wherein A represents:(a) C₁₋₃ alkanoyloxy; (b) C₁₋₃ alkoxy; (c) Cl or F; (d) hydrogen; (e) hydroxy; (f) carboxy ##STR15## (g) benzylcarboxy ##STR16## (h) 3-(hydroxycarbonyl)propanoyloxy; (i) hydroxycarbonylmethylaminocarbonyloxy; R₁ is(1) C₁₋₆ alkyl; (2) OR'₁ where R'₁ is(a) C₁₋₆ alkyl; (b) --C₆ H₅ ; (c) --CH₂ CH₂ C₆ H₅ ; or (d) ##STR17## where R represents hydrogen, C₁₋₆ alkyl, benzyl; (3) fluoro or chloro; B is OB₁ or NB₂ B₃ wherein B₁ and B₂ independently represent(1) benzyl; (2) methyl; (3) t-butyl; (4) CH₂ CH₂ CH═CH₂ or --CH₂ CH═C(CH₃)₂ ; (5) --CH₂ CH₂ CH₂ COO C₁₋₄ alkyl; B₃ is hydrogen or B₁ ; and Q is hydrogen.
 3. A method of treating or management of elastase-mediated conditions comprising the administration to a mammalian species in need of such treatment an effective amount of a compound of structural formula: ##STR18## wherein M is:(1) trifluoromethyl; (2) chloro or fluoro; (3) --COOM; (4) --CHO; (5) tosyloxy; or (6) --CH₂ A wherein A represents(a) hydrogen; (b) halo; (c) hydroxy; (d) C₁₋₆ alkoxy; (e) phenyloxy; (f) phenyl C₁₋₆ alkoxy; (g) unsubstituted or substituted mercapto of formula SR₅ wherein R₅ is H, C₁₋₆ alkyl, phenyl, benzyl, C₁₋₆ alkenyl, (h) --SCOR, --SCOOR or SCSOR wherein R is H or C₁₋₆ alkyl; (i) C₁₋₆ alkanoyloxy, benzylcarboxyloxy or phenylcarbonyloxy; (j) a substituted or unsubstituted amino or amido group selected from a group consisting of --NH₂, --CONHR, --CON(R)₂, --NHR, and --N(R)₂ ; (k) 3-(hydroxycarbonyl)propanoyloxy; (l) hydroxycarbonylmethylaminocarbonyloxy ##STR19## R₁ is (a) hydrogen; (b) OR'₁ wherein R'₁ is C₁₋₆ alkyl, phenyl or phenyl C₁₋₆ alkyl; ##STR20## where R represents H, C₁₋₆ alkyl, phenyl, benzyl, or C₁₋₆ alkylamino; (c) C₁₋₆ alkyl, phenyl or phenyl C₁₋₆ alkyl; (d) halo; B is OB₁ or NB₂ B₃ wherein B₁ and B₂ independently are:(a) straight or branched chain alkyl having from 1 to 6 carbon atoms; (b) phenyl; (c) cycloalkyl having from 3 to 8 carbon atoms; (d) alkenyl having from 2 to 8 carbon atoms; (e) cycloalkenyl having from 5 to 8 carbon atoms; (f) alkynyl having from 2 to 8 carbon atoms; (g) alkoxy alkyl having from 2 to 10 carbon atoms; (h) phenyl C₁₋₆ alkyl or C₁₋₆ alkylphenyl; (i) C₂₋₈ alkenylalkyl; (j) C₂₋₈ alkanoylalkyl; (k) C₂₋₈ alkanoyloxyalkyl; (l) C₁₋₆ alkoxycarboxylC₁₋₆ alkyl;the above groups (a)-(l) being unsubstituted or substituted by radicals such as alkyl, hydroxy, alkoxy, halo, nitro, mercapto, amino, substituted mono or diC₁₋₆ alkyl amino, cyano, carboxy, --SO₂ NH₂, carbamoyl, carbamoyloxy, alkylsulfonyl, alkylsulfinyl, sulfamoyl, azido, carboxamido or N-substituted carboxamido; B₃ is B₁ or hydrogen; and Q is(1) hydrogen; (2) C₁₋₆ alkyl; (3) haloC₁₋₆ alkyl; (4) hydroxy C₁₋₆ alkyl; (5) C₁₋₆ alkyl methylene, phenylmethylene, or phenylthiomethylene; (6) C₁₋₆ alkoxy C₁₋₆ alkyl; (7) benzyl; (8) phenylthio C₁₋₆ alkyl, phenylsulfinyl C₁₋₆ alkyl or phenylsulfonyl C₁₋₆ alkyl; (9) phenoxy C₁₋₆ alkyl; or (10) phenylamino C₁₋₆ alkyl.
 4. The method of claim 3 wherein:M is(1) trifluoromethyl; (2) chloro or fluoro; (3) formyl; (4) tosyloxy; (5) --CH₂ A wherein A represents:(a) C₁₋₃ alkanoyloxy; (b) C₁₋₃ alkoxy; (c) Cl or F; (d) hydrogen; (e) hydroxy; (f) carboxy ##STR21## (g) benzylcarboxy ##STR22## (h) 3-(hydroxycarbonyl)propanoyloxy; (i) hydroxycarbonylmethylaminocarbonyloxy; (1) C₁₋₆ alkyl; (2) OR'₁ where R'₁ is(a) C₁₋₆ alkyl; (b) --C₆ H₅ ; (c) --CH₂ CH₂ C₆ H₅ ; or (d) ##STR23## where R represents hydrogen, C₁₋₆ alkyl, benzyl; (3) fluor or chloro; B is OB₁ or NB₂ B₃ wherein B₁ and B₂ independently represent(1) benzyl; (2) methyl; (3) t-butyl; (4) --CH₂ CH₂ CH═CH₂ or --CH₂ CH═C(CH₃)₂ ; (5) --CH₂ CH₂ CH₂ COO C₁₋₄ alkyl; B₃ is hydrogen or B₁ ; and Q is hydrogen.
 5. The composition of claim 1 wherein the active compound is of formula ##STR24## wherein (a) when R₁ is --OCH₃, B is OCH₃ ;(b) when R₁ is --OCOC₆ H₅, B is --OCH₃ ; (c) when R₁ is --OCHO, B is --OCH₃ ; (d) when R₁ is --OCOCH₂ C₆ H₅, B is --OCH₃ ; (e) when R₁ is --OCHO, B is --OCH₂ CH₅ ; (f) when R₁ is --OCH₃, B is --OCH₂ (p-COOCH₃ --C₆ H₅); (g) when R₁ is --OCH₃, B is --O(CH₂)₃ COOCH₃ ; (h) when R₁ is --OCHO, B is --OtBu; or (i) when R₁ is --OCOCH₂ C₆ H₅ --, B is --OtBu.
 6. The composition of claim 1 wherein the active compound is(a) t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (b) t-Butyl 3-acetyloxymethyl-7α-formyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (c) t-Butyl 3-acetyloxymethyl-7α-acetyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (d) Methyl 3-chloro-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (e) Methyl 3-toxyloxy-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (f) t-Butyl 3-acetyloxymethyl-7α-fluoro-8-oxo-5-thia-1-axabicyclo[4.2.0]oct-2-ene-2-carboxylate; (g) t-Butyl 3-acetyloxymethyl-7α-chloro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (h) t-Butyl 30hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (i) t-Butyl 3-(3-[hydroxycarbonyl]propanoyloxymethyl)-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (j) t-Butyl 3-hydroxycarbonylmethylaminocarbonyloxy-methyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (k) t-Butyl 3-formyl-7αmethoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (l) t-Butyl 3-chloromethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (m) t-Butyl 3-methoxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (n) t-Butyl 3-methyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2ene-2-carboxylate; (o) t-Butyl 3-methyl-7β-amino-8-oxo-5-thia-1-azabicylo[4.2.0]oct-2-ene-2-carboxylate; (p) m-Methoxycarbonylbenzyl-3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (q) Ethoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (r) t-Butoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-2ene-2-carboxylate; (s) N-Benzyl-N-methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide; (t) N-(t-butoxycarbonyl)methyl 3-acetyloxyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide; (u) Benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (v) t-Butyl 3-acetyloxymethyl-7β-formamido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (w) t-Butyl 3-trifluoromethyl-7α-trifluoromethylcarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; or (x) p-Methoxybenzyl 3-methyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate.
 7. The method of treatment of claim 3 wherein the active compound is of formula ##STR25## wherein (a) when R₁ is --OCH₃, B is OCH₃ ;(b) when R₁ is --OCOC₆ H₅, B is --OCH₃ ; (c) when R₁ is --OCHO, B is --OCH₃ ; (d) when R₁ is --OCOCH₂ C₆ H₅, B is --OCH₃ ; (e) when R₁ is --OCHO, B is --OCH₂ C₆ H₅ ; (f) when R₁ is --OCH₃, B is --OCH₂ (p-COOCH₃ --C₆ H₅); (g) when R₁ is --CH₃, B is --O(CH₂)₃ COOCH₃ ; (h) when R₁ is --OCHO, B is --OtBu; or (i) when R₁ is --OCOCH₂ C₆ H₅ --, b is --OtBu.
 8. The method of treatment of claim 3 wherein the active compound is(a) t-Butyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (b) t-Butyl 3-acetyloxymethyl-7α-formyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (c) t-Butyl 3-acetyloxymethyl-7α-acetyloxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (d) Methyl 3-chloro-7αmethoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (e) Methyl 3-toxyloxy-7αmethoxy-8-oxo-5-thia-1azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (f) t-Butyl 3-acetyloxymethyl-7α-fluoro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (g) t-butyl 3-acetyloxymethyl-7α-chloro-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (h) t-Butyl 3-hydroxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (i) t-Butyl 3-(3-[hydroxycarbonyl]propanoyloxymethyl)-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (j) t-Butyl 3-hydroxycarbonylmethylaminocarbonyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (k) t-Butyl 3-formyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (l) t-Butyl 3-chloromethyl-7αmethoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (m) t-Butyl 3-methoxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-3-ene-2-carboxylate; (n) t-Butyl 3-methyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (o) t-Butyl 3-methyl-7βamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (p) m-Methoxycarbonylbenzyl-3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (q) Ethoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (r) t-Butoxycarbonylmethyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (s) N-Benzyl-N-methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide; (t) N-(t-Butoxycarbonyl)methyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxamide; (u) Benzyl 3-acetyloxymethyl-7α-methoxy-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (v) t-Butyl 3-acetyloxymethyl-7α-formamido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; (w) t-Butyl 3-trifluoromethyl-7α-trifluoromethylcarbonylamino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate; or (x) p-Methoxybenzyl 3-methyl-7α-azido-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-carboxylate. 